AU
B168B00

DTC B168B00 indicates the SRS (airbag system) control module detects invalid configuration parameters for Airbag Loop 7 — Qin Plus

Safety System

DTC B168B00 indicates the SRS (airbag system) control module detects invalid configuration parameters for Airbag Loop 7.

In the BYD Qin PRO SRS architecture, Loop 7 typically corresponds to the right front seat side airbag or the right rear side curtain module.

During self-diagnosis, the SRS control module detects that the loop's electrical impedance, squib resistance, or configuration coding does not match the calibrated value (typically 2.0-3.0Ω), or the configuration data stored in the module's internal EEPROM is corrupted or missing.

This is a configuration validity fault rather than a simple open or short circuit.

This fault can prevent the corresponding airbag from deploying during a collision, illuminates the airbag warning lamp continuously, and forces the system into fail-safe mode.

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Cases Logged
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Causes
Likely Causes — Qin Plus
  • 1Abnormal internal igniter resistance in the Circuit 7 airbag component (seat airbag or curtain airbag) due to aging, moisture ingress, or incorrect model, causing impedance to fall outside the standard 1.6-3.5Ω range.
  • 2Poor wiring harness connector contact, especially at the yellow under-seat SRS connector (G07 or GJK20 series), where frequent seat movement causes terminal pin back-out, oxidation, or intermittent contact.
  • 3SRS control module software version defect (early versions contain a configuration verification algorithm flaw) or power fluctuations (low battery voltage, incorrect jump-starting) corrupted the internal module configuration data.
  • 4Incorrect replacement airbag module installed after accident repairs or seat/interior removal and installation (e.g., fitting a high-trim airbag to a low-trim vehicle), or failure to perform the correct SRS system configuration (coding).
  • 5Low 12V battery voltage (below 9V) or excessive voltage drop in the power supply circuit prevents the SRS module from correctly reading the loop configuration parameters during initialization.
What To Do
  • 1
    Use the VDS2000/VDS2100 diagnostic tool to read the complete fault codes and freeze frame data. Record environmental data at the time the fault occurred, including vehicle speed, voltage, and temperature. Confirm whether the fault is Current rather than History.
  • 2
    Check the SRS system power supply: measure the battery voltage (should be ≥12.4V), check if instrument panel fuses F2/3 (SRS power) and F2/4 (SRS ignition power) are blown, and verify ground points G201 and G301 are tight and free of oxidation.
  • 3
    Refer to the BYD workshop manual wiring diagram to identify the specific airbag component for Circuit 7 (typically the right front seat side airbag on the Qin PRO). Disconnect the battery negative terminal and wait at least 90 seconds. Remove the airbag component. Measure the resistance between the two squib terminals (standard value: 2.0 ± 0.3 Ω). Measure the insulation resistance between the terminals and the housing (should be >10 MΩ).
  • 4
    Check wiring harness continuity: Focus on the yellow SRS connector under the seat (marked GJK20 or G07). Inspect the pins for push-out, oxidation, or water ingress. Measure the harness resistance between the SRS module and the airbag connector (should be <1Ω). Check CAN-H and CAN-L for short to ground.
  • 5
    Check the SRS control module software version against the BYD technical bulletin. If the version is lower than V3.2 (refer to the latest TSB for the exact version), perform a software upgrade. After the upgrade, perform the "SRS System Configuration" special function and rewrite the vehicle configuration code (Coding).
  • 6
    If the wiring harness and airbag assembly are normal, replace the SRS control module (select the part number based on vehicle configuration, e.g., 5A-3636100A). After replacement, perform configuration, coding, and system calibration.
  • 7
    Clear the fault code. Use the diagnostic tool to perform the "SRS System Self-Test" (Active Test) and verify the Circuit 7 status displays "Normal". Perform a road test simulating bumpy road conditions to confirm the fault does not recur.
Real-World Cases
BYD DTC AI Analysis

Qin Pro DM: Water ingress into the under-seat connector caused a Circuit 7 fault.

✓
A 2019 Qin Pro DM with 32,000 km showed a constant airbag warning light on the instrument panel. The retrieved DTC was B168B00 (Loop 7 invalid configuration). Inspection found damp carpet under the right front seat. Disassembly revealed water stains inside SRS harness connector GJK20. Pins 14 (Loop 7 high) and 15 (Loop 7 low) had green copper corrosion, increasing contact resistance to 5.6 Ω, beyond the SRS module threshold. Repair: cleaned the connector with electronic cleaner, blew it dry, applied conductive protective grease, and replaced the waterproof seal under the seat. Fault cleared.
BYD DTC AI Analysis

Qin Pro petrol: Missing coding after accident repair caused configuration error.

✓
A 2018 Qin PRO petrol had a right front side collision. The shop replaced the right front seat airbag and SRS control module. Afterwards, they pulled DTC B168B00. Diagnosis found the new SRS module was a generic part and had not been written with vehicle configuration. They used the VDS diagnostic tool to enter Special Functions → SRS Configuration, entered the correct configuration code 0x07 (example value) based on the VIN and specification table (high/low spec, with/without side curtain airbags), and executed the coding. The fault code cleared automatically and the system passed self-test.
BYD DTC AI Analysis

SRS module data loss after battery drain

✓
A 2019 Qin PRO DM sat for an extended period, causing the 12V battery to discharge to 8.5V. After a jump-start, the airbag warning light stayed on, and it logged DTC B168B00 along with multiple loop configuration faults. Inspection found that the SRS module failed to initialize during the low-voltage start, resulting in internal configuration data validation errors. Repair steps: Replaced the 12V battery (too deeply discharged to recover). Cleared fault codes with a diagnostic tool – no effect. Performed a power reset on the SRS module by disconnecting its power for over 10 minutes. After reconnecting, ran the "System Configuration" and "Collision Data Clear" procedures. Fault fixed.
BYD DTC AI Analysis

Aftermarket seat heater pad caused abnormal circuit impedance

✓
The owner of a 2018 BYD Qin PRO (petrol) added seat heating at an unauthorised workshop. The tech cut into the SRS loop wiring to connect it, placing extra resistance in parallel with Loop 7. The SRS module measured total loop resistance at 1.2 Ω (below the 1.6 Ω lower limit) and flagged an invalid configuration. Fix: Removed the illegal wiring, repaired the SRS harness with solder and heat shrink tubing, and rerouted the harness back to factory routing. Fault cleared. Warning: Never cut into or modify SRS harness wiring.
Other Qin Plus Fault Codes
B1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.